Antitumor activity of alkylphospholipid edelfosine in prostate cancer models and endoplasmic reticulum targeting

Design, synthesis and evaluation of acetylcholine-antitumor lipid hybrids led to identification of a potential anticancer agent disrupting the CDK4/6-Rb pathway in lung cancer

Hybridization of acetylcholine with antitumor lipids (ATLs) was explored to achieve novel potential anticancer agents. The combination with a 2-stearoxyphenyl moiety substantially enhanced the anticancer activity of the acetylcholine hybrids. Compounds 6, 8, 9 and 10 exhibited pronounced anticancer activities higher than edelfosine and stPEPC and NSC43067. Compounds 6, 8, 9 and 10 also showed broad-spectrum anticancer activity against diverse cancer cells including lung, ovarian, renal, prostate, leukaemia, colon, CNS, melanoma, and breast cancer cells. Compounds 6 and 8 were potent compounds eliciting single digit low micromolar GI50 values. Compound 6 was the most potent against non-small cell lung cancer, ovarian cancer, renal cancer, and prostate cancer. Meanwhile, compound 8 was the most potent against leukaemia, colon cancer, CNS cancer, melanoma, and breast cancer. Exploration of the mechanism of action of compound 6 in A549 non-small cell lung cancer cells showed that it triggers cell cycle arrest in the G0/G1 phase via disruption of the CDK4/6-Rb pathway and induces apoptosis via the activation of caspases, upregulation of BAX and cleavage of PARP. Overall, the results present acetylcholine-ATL hybrids 6 and 8 as potential anticancer agents for possible further development.

Isolinderalactone suppresses pancreatic ductal adenocarcinoma by activating p38 MAPK to promote DDIT3 expression and trigger endoplasmic reticulum stress

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies worldwide, and its incidence rate is increasing. PDAC patients are prone to acquired chemotherapy resistance, necessitating the development of novel drugs to provide alternative treatment options. In recent years, traditional folk medicine and its active ingredients have garnered increasing attention for their effectiveness in treating tumors. Here, we discovered that isolinderalactone (ILL), a sesquiterpenoid compound extracted from the traditional Chinese medicine Lindera aggregata (Sims) Kosterm., possesses anti-PDAC pharmacological activity. Our results revealed that ILL decreased the proliferative capacity of PDAC cells in a time- and dose-dependent manner. The migration and invasion abilities of tumor cells were significantly suppressed due to the inhibition of epithelial-to-mesenchymal transition (EMT). Additionally, the cell cycle was arrested in the G2/M phase, leading to apoptosis, and inhibiting inflammatory responses. Mechanistically, bioinformatics analysis of molecular expression changes combined with in vivo and in vitro experiments demonstrated that ILL induces persistent ER stress by activating p38 MAPK signaling pathway, thus promoting the expression of DDIT3, and ultimately suppressing progression-related cell behaviors. Animal experiments confirmed that ILL also inhibited PDAC development in vivo with minimal toxicity. In summary, our study identified ILL as a potential therapeutic compound for PDAC treatment.

Suppression of metastatic organ colonization and antiangiogenic activity of the orally bioavailable lipid raft-targeted alkylphospholipid edelfosine

Metastasis is the leading cause of cancer mortality. Metastatic cancer is notoriously difficult to treat, and it accounts for the majority of cancer-related deaths. The ether lipid edelfosine is the prototype of a family of synthetic antitumor compounds collectively known as alkylphospholipid analogs, and its antitumor activity involves lipid raft reorganization. In this study, we examined the effect of edelfosine on metastatic colonization and angiogenesis. Using non-invasive bioluminescence imaging and histological examination, we found that oral administration of edelfosine in nude mice significantly inhibited the lung and brain colonization of luciferase-expressing 435-Lung-eGFP-CMV/Luc metastatic cells, resulting in prolonged survival. In metastatic 435-Lung and MDA-MB-231 breast cancer cells, we found that edelfosine also inhibited cell adhesion to collagen-I and laminin-I substrates, cell migration in chemotaxis and wound-healing assays, as well as cancer cell invasion. In 435-Lung and other MDA-MB-435-derived sublines with different organotropism, edelfosine induced G2/M cell cycle accumulation and apoptosis in a concentration- and time-dependent manner. Edelfosine also inhibited in vitro angiogenesis in human and mouse endothelial cell tube formation assays. The antimetastatic properties were specific to cancer cells, as edelfosine had no effects on viability in non-cancerous cells. Edelfosine accumulated in membrane rafts and endoplasmic reticulum of cancer cells, and membrane raft-located CD44 was downregulated upon drug treatment. Taken together, this study highlights the potential of edelfosine as an attractive drug to prevent metastatic growth and organ colonization in cancer therapy. The raft-targeted drug edelfosine displays a potent activity against metastatic organ colonization and angiogenesis, two major hallmarks of tumor malignancy.

Brusatol induces ferroptosis in oesophageal squamous cell carcinoma by repressing GSH synthesis and increasing the labile iron pool via inhibition of the NRF2 pathway

Brusatol (Bru), a bioactive compound found in Brucea sumatrana, exerts antitumour effects on several malignancies. However, the role and molecular mechanism of Bru in squamous cell carcinoma of the oesophagus (ESCC) remain unclear. Here, we found that Bru decreased the survival of ESCC cells. Subsequently, the ferroptosis inhibitors, deferoxamine and liproxstatin-1, rescued Bru-induced cell death, indicating that ferroptosis plays a major role in Bru-induced cell death. Furthermore, Bru promoted lipid peroxidation, glutathione (GSH) depletion, and ferrous iron overload in vitro. Consistent with these in vitro results, Bru significantly inhibited tumour growth in KYSE150 xenograft nude mice by triggering ferroptosis. Mechanistically, nuclear factor E2-related factor 2 (NRF2) inactivation via increased ubiquitin-proteasome degradation was found to be a vital determinant of ferroptosis induced by Bru. Notably, Bru significantly decreases GSH synthesis, iron storage, and efflux by downregulating the expression of NRF2 target genes (glutamate-cysteine ligase catalytic subunit (GCLC), solute carrier family 7 member 11 (SLC7A11), ferritin heavy chain 1 (FTH1), and solute carrier family 40 member 1 (SLC40A1)), resulting in the accumulation of lethal lipid-based reactive oxygen species (ROS) and intracellular enrichment of chelated iron. Taken together, our findings indicate that ferroptosis is a novel mechanism underlying Bru-induced antitumour activity and will hopefully provide a valuable compound for ESCC treatment.